The present invention relates to system boards for a computer, and in particular, to riser cards that connect to the system board and accept adapters that are plugged into the riser card instead of the system board.
Heating is a constant and significant issue to be addressed in digital data processors. The failure rates of many electronic components increase as operating temperatures rise. This is particularly true of central processing units which, themselves, often generate significant heat. The problem is compounded by the use of more densely packed circuit boards, more compact, lower profile housings, more densely packed components within a chassis, and faster processing chips or higher speed processor devices.
Most often, processors and associated components are cooled by airflow. Fans are typically used to push or pull air from one side of a chassis, across the components, and out the other side of the chassis. Thus, for example, a typical digital data processor includes chassis intake and/or exhaust fans, often with a fan on the central processing unit itself. While the steps of simply providing intake and exhaust fans on a chassis or housing wall, and of providing one or more device fans on critical components, have proven adequate to date, obtaining sufficient circulation for adequate heat dissipation requires careful design, and the limits of achievable cooling are taxed as even more powerful processors, and/or more compact or constricted systems are built.
The expansion capabilities of a typical digital data processing unit give rise to additional air flow problems. For example, peripheral component interconnect (PCI) cards, which connect directly into a digital data processor circuit board, or motherboard, allow additional components, e.g. expansion boards, to be installed within the unit. These additional components occupy regions that would otherwise be open to circulation, and create a more densely packed arrangement of components, which further prevents the flow of air. Often, because of path length restrictions, the additional expansion boards must be positioned at specific locations, which are not necessarily conducive to proper circulation.
One area of particular concern arises for web servers and for specialized digital data processing apparatus, such as storage arrays used in web servers, wherein tens or hundreds of closely packed substantially identical cards or devices such as CD ROM units may be mounted in small or constricted spaces, e.g., in a chassis mounted in a rack or cabinet. By way of example, a single closed box-like chassis may have ten or more CD ROM devices with their associated control cards and one or more power supplies, and each chassis may mount like a slide in drawer into a rack holding ten or more such chassis stacked in a column. These chassis have a standard width (e.g. 19 inches) and a standardized height (1U, 2U or 3U), with the thinnest of such units having a height barely 2 inches tall. Such assemblies present extreme challenges for efficient layout of internal busses and components, and for providing adequate cooling in the restricted space allotted to each multi-device chassis in the array.
Accordingly, there is a need to provide for more powerful, and/or more compact systems with air ventilation paths.
One object of the present invention is to provide an improved digital data processor apparatus and method.
A more particular object is to provide such apparatus and methods as are particularly adapted to web servers and other data processing apparatus that are compact of design and/or not prone to overheating.
A still further object is to provide such apparatus and methods as can be implemented at low cost.
A still further object of the invention is to provide such apparatus and methods as can be adapted to pre-existing equipment, as well as designed for use in new equipment.
One or more of the foregoing objects are achieved in accordance with the present invention which provides, in one aspect, a PCI riser card that connects to a circuit board and has a first and a second connector attached to opposing sides of the card for each connecting, respectively, to a first and a second expansion board.
In one embodiment, the first connector is inverted with respect to the second connector. The first and second connectors can be female connectors that are each matable with a corresponding male connector mounted, for example, on an expansion board. Alternatively, the connectors may be male pin connectors, or may be of two opposite types. Preferably, however, both connectors are of the same type and are configured for connecting two identical expansion boards. The first connector can be offset from the second connector. The expansion boards, when mated with their corresponding connectors, are substantially parallel to the circuit board. The first expansion board can be inverted (i.e., upside down) with respect to the second expansion board.
The riser card of the present invention is advantageous in that the mounting of two expansion boards consumes less space than in the prior art since only one riser card is required per two expansion boards. This provides additional space for air flow to travel.
In another aspect of the present invention, a module such as a circuit board is disposed in a chassis, and an expansion slot is mounted on the circuit board and adapted for receiving a riser card. The riser card mounts in the expansion slot, and has a first connector and a second connector attached to opposing sides of the card that receive respective expansion boards, which extend in opposite directions from the riser card and parallel to the circuit board. The expansion slot may be disposed centrally on the circuit board to define shortened bus paths to the two expansion boards. The mounting geometry also defines two air flow channels along two sides of the board.